Another batch of changes that should make the SST process
more reliable in all scenarios:

 1) Added hostname or CN verification when stunnel is used
    with certificate chain verification (verifyChain = yes);
 2) Added check for the absence of the stunnel utility for
    mtr tests;
 3) Deletion of working files before and after SST is done
    more accurately;
 4) rsync on joiner can be run even if the path to its
    configuration file contains spaces;
 5) More accurate directory creation (for data files and
    for logs);
 6) IST with mysqldump no longer turns off statement logging;
 7) Reset password for mysqldump when password is empty but
    username is specified;
 8) More reliable quoting when generating statements in
    wsrep_sst_mysqldump;
 9) Added explicit generation of 2048-bit Diffie-Hellman
    parameters for sockat < 1.7.3, by analogy with xtrabackup;
10) Compression parameters for qpress are read from all
    suitable server groups in configuration file, as well as
    from the [sst] and [xtrabackup] groups;
11) Added a test that checks compression using qpress;
12) Checking for optional utilities is modified to work even
    if they implemented as built-in shell commands (unlikely
    on real systems, but more reliable).

MDEV-25562 Assertion `pause_seqno_.is_undefined() == false' failed in void wsrep::server_state::resume()

If pause() is not executed in galera and returns seqno = -1 we should
skip resume().

The functions fil_file_readdir_next_file(), os_file_opendir(),
os_file_closedir() became dead code in the server in MariaDB 10.4.0
with commit 09af00cb (the removal of
the crash recovery logic for the TRUNCATE TABLE implementation that
was replaced in MDEV-13564).

os_file_opendir(), os_file_closedir(): Define as macros.

ha_innobase::index_read(): If an autocommit non-locking transaction was
already started, refuse to access a SPATIAL INDEX.
Once a non-locking autocommit transaction has started, it must remain
in that mode (not acquire any locks).

This should fix one cause of the assertion failure that would occur in
DeadlockChecker::check_and_resolve() under heavy load, presumably
due to concurrent execution of trx_commit_in_memory().

Fixed bugs caused by inaccuracies in automatic merging
from other branches:

1) Authentication information is not removed from the connection
   address, which causes some tests to fail;
2) wsrep_debug=on should be replaced with wsrep_debug=1;
3) Added missing "connection" lines to test result file;
4) Some tests have been corrected for Galera 4.x (10.4+).

1) This commit implements reading all sections from configuration
files while looking for the current value of any server variable,
which were previously only read from the [mysqld.suffix] group and
from [mysqld], but not from other groups such as [mariadb.suffix],
[mariadb] or, for example, [server].

2) This commit also fixes misrecognition of some parameters when
parsing a command line containing a special marker for the end
of the list of options ("--") or when short option names (such
as "-s", "-a" and "-h arg") chained together (like a "-sah arg").
Such parameters can be passed to the SST script in the list of
arguments after "--mysqld-args" if the server is started with a
complex set of options - this was revealed during manual testing
of changes to read configuration files.

3) The server-side preparation code for the "--mysqld-args"
option list has also been simplified to make it easier to change
in the future (if needed), and has been improved to properly
handle the special backquote ("`") character in the argument
values.

1) This commit implements reading all sections from configuration
files while looking for the current value of any server variable,
which were previously only read from the [mysqld.suffix] group and
from [mysqld], but not from other groups such as [mariadb.suffix],
[mariadb] or, for example, [server].

2) This commit also fixes misrecognition of some parameters when
parsing a command line containing a special marker for the end
of the list of options ("--") or when short option names (such
as "-s", "-a" and "-h arg") chained together (like a "-sah arg").
Such parameters can be passed to the SST script in the list of
arguments after "--mysqld-args" if the server is started with a
complex set of options - this was revealed during manual testing
of changes to read configuration files.

3) The server-side preparation code for the "--mysqld-args"
option list has also been simplified to make it easier to change
in the future (if needed), and has been improved to properly
handle the special backquote ("`") character in the argument
values.

This commit contains a large set of further bug fixes and
improvements to SST scripts for Galera, continuing the work
that was started in MDEV-24962 to make SST scripts work smoothly
in different network configurations (especially using ipv6) and
with different environment settings:

 1) The ipv6 addresses were incorrectly handled in the SST script
    for rsync (incorrect address substitution for establishing a
    connection, incorrect address substitution for bind, and so on);
 2) Checking the locality of the ip-address in SST scripts did not
    support ipv6 addresses (such as "[::1]"), which were falsely
    identified as non-local ip, which further did not allow running
    two SSTs on different local addresses on the same machine.
    On the other hand, this bug masked some other errors (related
    to handling ipv6 addresses);
 3) The code for checking the locality of the ip address was different
    in the SST scripts for rsync and for mysqldump, with individual
    flaws. This code is now made common and moved to wsrep_sst_common;
 4) Waiting for the start of the transport channel (socat, nc, rsync,
    stunnel) in the wait_for_listen() and check_pid_and_port() functions
    did not process ipv6 addresses correctly in all cases (not for all
    branches);
 5) Waiting for the start of the transport channel (socat, nc, rsync,
    stunnel) in the wait_for_listen() and check_pid_and_port() functions
    for some code branches could give a false positive result due to
    the textual match of prefixes in the port number and/or PID of
    the process;
 6) Waiting for the start of the transport channel (socat, nc, rsync,
    stunnel) was supported through different utilities in SST scripts
    for mariabackup and for rsync, and with various minor flaws in
    the code. Now the code is still different in these scripts, but
    it supports a common set of utilities (lsof, ss, sockstat) and
    is synchronized across patterns that used to check the output
    of  these utilities;
 7) In SST via mariabackup, the signal about readiness to receive data
    is sometimes sent too early - immediately after listen(), and not
    after accept() (which are called by socat or netcat utility).
 8) Checking availability of the some options of some utilities was
    done using the grep pattern, which easily gives false positives;
 9) Common name (CN) for local addresses, if not explicitly specified,
    is now always replaced to "localhost" to avoid the need to generate
    many separate certificates for local addresses of one machine and
    not to depend on which the local address is currently used in test
    (ipv4 or ipv6, etc.);
10) In tests galera_sst_mariabackup_encrypt_with_key_server and
    galera_sst_rsync_encrypt_with_key_server the correct certificate
    is selected to avoid commonname (CN) mismatch problems;
11) Further refactoring to protect against spaces in file names.
12) Further general refactoring to eliminate bash-specific constructs
    or to improve code readability;
13) The code for setting options for the nc (netcat) utility was
    different in different scripts for SST - now it is made identical.
14) Fixed long-time broken encryption via xbcrypt in combination with
    mariabackup and added support for key-based encryption via openssl
    utility, which is now enabled by default for encrypt=1 mode (this
    default mode can be changed using a new configuration file option
    "encypt-format=openssl|xbcrypt", which can be placed in the [mysqld],
    [sst] or in the [xtrabackup] section) - this change will allow us
    to use and to test the encypt=1 encryption without installing
    non-standard third-party utilities.

Problem:
========
Aborting OPTIMIZE TABLE still logs in binary logs and replicates to the
Slave server. "Optimize table" command under execution, is killed by using
"Ctrl-C" as shown below.

MariaDB [test]> optimize table t2;
^CCtrl-C -- query killed. Continuing normally.

In spite of query execution being interrupted the query gets written to
binary log.

Analysis:
========
Admin command execution logic is not handling KILL command, hence it
ignores the KILL command and completes its execution.

Fix:
===
Check for thread killed notification, during admin command execution and
handle it. If thread kill occurs prior to any table modification the query
will not be written to binary log. If kill happens after at least one table
is modified then the query will be written to binary log. Ex: command in
execution is 'OPTIMIZE TABLE t1,t2' and the thread kill happens after t1
table is modified then 'OPTIMIZE TABLE t1,t2' will be written to binary log
as admin commands will not make the slave to diverge from master.

Problem:
=======
In slave_parallel_mode=optimistic configuration, when admin commands and
DML operation on the same table are scheduled simultaneously for execution,
it results in lock conflict and slave server either hangs due to
deadlock or goes down with an assert.

Analysis:
========
Admin commands OPTIMIZE, REPAIR and ANALYZE are written to binary log as
ordinary transactions. When 'slave_parallel_mode' is 'optimistic' DMLs are
allowed to run in parallel. But these locks are not detected by parallel
replication deadlock detection-and-handling mechanism. At times they result
in deadlock or assertion.

Fix:
===
Flag admin commands as DDL in Gtid_log_event at the time of writing to
binary log. Add a new bit EXECUTED_TABLE_ADMIN_CMD to
'm_unsafe_rollback_flags'. During 'mysql_admin_table' command execution it
accepts a list of tables to be processed and executes them in a loop. Upon
successful execution enable 'EXECUTED_TABLE_ADMIN_CMD' bit in
thd->transaction.stmt_unsafe_rollback_flags. Gtid_log_event constructor
will notice this flag and mark the current transaction with 'FL_DDL' flag.
Gtid_log_events marked as FL_DDL will not be scheduled parallel execution,
on the slave. They will execute in isolation to prevent deadlocks.

Note: Removed the call to 'trans_commit_implicit' from 'mysql_admin_table'
function as 'mysql_execute_command' will take care of invoking
'trans_commit_implicit'.

No longer a MySQL server, "his" is the wrong pronoun
for a server.

Thanks Michael Newton for highlighting these problems

Also changed slave -> replica.

1) This commit implements reading all sections from configuration
files while looking for the current value of any server variable,
which were previously only read from the [mysqld.suffix] group and
from [mysqld], but not from other groups such as [mariadb.suffix],
[mariadb] or, for example, [server].

2) This commit also fixes misrecognition of some parameters when
parsing a command line containing a special marker for the end
of the list of options ("--") or when short option names (such
as "-s", "-a" and "-h arg") chained together (like a "-sah arg").
Such parameters can be passed to the SST script in the list of
arguments after "--mysqld-args" if the server is started with a
complex set of options - this was revealed during manual testing
of changes to read configuration files.

3) The server-side preparation code for the "--mysqld-args"
option list has also been simplified to make it easier to change
in the future (if needed), and has been improved to properly
handle the special backquote ("`") character in the argument
values.

If a select query contained an ORDER BY clause that followed a LIMIT clause
or an ORDER BY clause or ORDER BY with LIMIT the EXPLAIN output for the
query showed an execution plan different from that was actually executed.

Approved by Roman Nozdrin <roman.nozdrin@mariadb.com>

Problem:- When slave is shutdown, we will get this assertion failure
sql/sql_list.h:642: void ilink::assert_linked(): Assertion `prev != 0
&& next != 0' failed.

Solution:- In close_connections when we call threads.get() it resets to
prev and next to NULL. And in parallel worker thread(handle_rpl_parallel_thread)
calls unlink_not_visible_thd() which assert on prev and next being not NULL.
.unlink_not_visible_thd() should be always called first before threads.get()
is called. To make sure worker calls unlink_not_visible_thd() in
slave_prepare_for_shutdown() we are deactivating the  worker thread pool
which in turn will close all worker threads. Since this is already done in 10.4
and 10.5 I am backPorting MDEV-20821 and MDEV-22370 to 10.2. Mdev-22370
is improving the MDEV-20821 patch.

MDEV-22370 safe_mutex: Trying to lock uninitialized mutex at /data/src/10.4-bug/sql/rpl_parallel.cc, line 470 upon shutdown during FTWRL

Problem:- When we issue FTWRL with shutdown in parallel, there is race between
FTWRL and shutdown. Shutdown might destroy the mutex (pool->LOCK_rpl_thread_pool)
before FTWRL can lock it. So we can get crash on FTWRL thread

Solution:- mysql_mutex_destroy(pool->LOCK_rpl_thread_pool) should wait for
FTWRL thread to complete its work , and then destroy.
So slave_prepare_for_shutdown will just deactivate the pool, and mutex is destroyed
later in end_slave()

Parallel slave server shutdown found to be hanging in
close_connections() triggered by shutdown due to a slave worker thread
would not be notified to exit in case the worker was sitting idle.

Fixed with destroying the worker pool earlier that is in
slave_prepare_for_shutdown() when all their driver threads have already left.
A test file is added to simulate the bug condition as well as check
multi-sourced and not-idle worker cases.

This commit contains a large set of further bug fixes and
improvements to SST scripts for Galera, continuing the work
that was started in MDEV-24962 to make SST scripts work smoothly
in different network configurations (especially using ipv6) and
with different environment settings:

 1) The ipv6 addresses were incorrectly handled in the SST script
    for rsync (incorrect address substitution for establishing a
    connection, incorrect address substitution for bind, and so on);
 2) Checking the locality of the ip-address in SST scripts did not
    support ipv6 addresses (such as "[::1]"), which were falsely
    identified as non-local ip, which further did not allow running
    two SSTs on different local addresses on the same machine.
    On the other hand, this bug masked some other errors (related
    to handling ipv6 addresses);
 3) The code for checking the locality of the ip address was different
    in the SST scripts for rsync and for mysqldump, with individual
    flaws. This code is now made common and moved to wsrep_sst_common;
 4) Waiting for the start of the transport channel (socat, nc, rsync,
    stunnel) in the wait_for_listen() and check_pid_and_port() functions
    did not process ipv6 addresses correctly in all cases (not for all
    branches);
 5) Waiting for the start of the transport channel (socat, nc, rsync,
    stunnel) in the wait_for_listen() and check_pid_and_port() functions
    for some code branches could give a false positive result due to
    the textual match of prefixes in the port number and/or PID of
    the process;
 6) Waiting for the start of the transport channel (socat, nc, rsync,
    stunnel) was supported through different utilities in SST scripts
    for mariabackup and for rsync, and with various minor flaws in
    the code. Now the code is still different in these scripts, but
    it supports a common set of utilities (lsof, ss, sockstat) and
    is synchronized across patterns that used to check the output
    of  these utilities;
 7) In SST via mariabackup, the signal about readiness to receive data
    is sometimes sent too early - immediately after listen(), and not
    after accept() (which are called by socat or netcat utility).
 8) Checking availability of the some options of some utilities was
    done using the grep pattern, which easily gives false positives;
 9) Common name (CN) for local addresses, if not explicitly specified,
    is now always replaced to "localhost" to avoid the need to generate
    many separate certificates for local addresses of one machine and
    not to depend on which the local address is currently used in test
    (ipv4 or ipv6, etc.);
10) In tests galera_sst_mariabackup_encrypt_with_key_server and
    galera_sst_rsync_encrypt_with_key_server the correct certificate
    is selected to avoid commonname (CN) mismatch problems;
11) Further refactoring to protect against spaces in file names.
12) Further general refactoring to eliminate bash-specific constructs
    or to improve code readability;
13) The code for setting options for the nc (netcat) utility was
    different in different scripts for SST - now it is made identical.
14) Fixed long-time broken encryption via xbcrypt in combination with
    mariabackup and added support for key-based encryption via openssl
    utility, which is now enabled by default for encrypt=1 mode (this
    default mode can be changed using a new configuration file option
    "encypt-format=openssl|xbcrypt", which can be placed in the [mysqld],
    [sst] or in the [xtrabackup] section) - this change will allow us
    to use and to test the encypt=1 encryption without installing
    non-standard third-party utilities.

This commit contains a large set of further bug fixes and
improvements to SST scripts for Galera, continuing the work
that was started in MDEV-24962 to make SST scripts work smoothly
in different network configurations (especially using ipv6) and
with different environment settings:

 1) The ipv6 addresses were incorrectly handled in the SST script
    for rsync (incorrect address substitution for establishing a
    connection, incorrect address substitution for bind, and so on);
 2) Checking the locality of the ip-address in SST scripts did not
    support ipv6 addresses (such as "[::1]"), which were falsely
    identified as non-local ip, which further did not allow running
    two SSTs on different local addresses on the same machine.
    On the other hand, this bug masked some other errors (related
    to handling ipv6 addresses);
 3) The code for checking the locality of the ip address was different
    in the SST scripts for rsync and for mysqldump, with individual
    flaws. This code is now made common and moved to wsrep_sst_common;
 4) Waiting for the start of the transport channel (socat, nc, rsync,
    stunnel) in the wait_for_listen() and check_pid_and_port() functions
    did not process ipv6 addresses correctly in all cases (not for all
    branches);
 5) Waiting for the start of the transport channel (socat, nc, rsync,
    stunnel) in the wait_for_listen() and check_pid_and_port() functions
    for some code branches could give a false positive result due to
    the textual match of prefixes in the port number and/or PID of
    the process;
 6) Waiting for the start of the transport channel (socat, nc, rsync,
    stunnel) was supported through different utilities in SST scripts
    for mariabackup and for rsync, and with various minor flaws in
    the code. Now the code is still different in these scripts, but
    it supports a common set of utilities (lsof, ss, sockstat) and
    is synchronized across patterns that used to check the output
    of  these utilities;
 7) In SST via mariabackup, the signal about readiness to receive data
    is sometimes sent too early - immediately after listen(), and not
    after accept() (which are called by socat or netcat utility).
 8) Checking availability of the some options of some utilities was
    done using the grep pattern, which easily gives false positives;
 9) Common name (CN) for local addresses, if not explicitly specified,
    is now always replaced to "localhost" to avoid the need to generate
    many separate certificates for local addresses of one machine and
    not to depend on which the local address is currently used in test
    (ipv4 or ipv6, etc.);
10) In tests galera_sst_mariabackup_encrypt_with_key_server and
    galera_sst_rsync_encrypt_with_key_server the correct certificate
    is selected to avoid commonname (CN) mismatch problems;
11) Further refactoring to protect against spaces in file names.
12) Further general refactoring to eliminate bash-specific constructs
    or to improve code readability;
13) The code for setting options for the nc (netcat) utility was
    different in different scripts for SST - now it is made identical.
14) Fixed long-time broken encryption via xbcrypt in combination with
    mariabackup and added support for key-based encryption via openssl
    utility, which is now enabled by default for encrypt=1 mode (this
    default mode can be changed using a new configuration file option
    "encypt-format=openssl|xbcrypt", which can be placed in the [mysqld],
    [sst] or in the [xtrabackup] section) - this change will allow us
    to use and to test the encypt=1 encryption without installing
    non-standard third-party utilities.

This is incosistent with other single config generators, where
the default type has always been RelWithDebInfo.

Fixed by moving setting of CMAKE_BUILD_TYPE right before PROJECT.

unless explicitly overruled with -DWITH_JEMALLOC=no

XA transaction only allows to access data in specific states,
in ACTIVE, but not in IDLE or PREPARE.

But even then one should be able to run SHOW STATUS.